An existing optical system 45 is described with respect to FIG. 1. In system 45, light from one or more substantially polarized solid state light sources 44a, 44b are combined by beam combiners 30. The combined light from sources 44a is subsequently rotated by retardation plate 64 such that its polarization is orthogonal to the combined light from sources 44b. The orthogonally polarized combined light from sources 44a and 44b next impinge upon rotating disk 65, which contains at least one segment that is transmissive and one that is reflective to the light. In one case, whereby disk 65 is rotated such that the reflective segment encounters the combined light from sources 44a and 44b, the combined light from sources 44a will be directly reflected onto the optical axis 3 and directed toward lens 50 for either optical integration (not shown) or illumination of the remaining optical system (not shown). The combined light from sources 44b, however, will be redirected to reflective surface 72 and further passed through retardation plate 64, which rotates the polarization to substantially the same state as the combined light from sources 44a. The light exiting retardation plate 64 is substantially directed onto a similar optical path of the combined light from sources 44a and is sent through lens 50.
In the alternative case, whereby disk 65 is rotated such that the transmissive segment is in the path of the combined light from sources 44a and 44b, the situation is reversed such that the combined light from sources 44a is redirected and rotated to the polarization state of the combined light from sources 44b before both are sent to lens 50. In this case, the rotating segmented disk 65 alternately delivers two orthogonal states of polarization to lens 50 for use in an optical system.
The system 45, however, exhibits increased etendue 2, which may not be preferable in certain applications. Accordingly, a need in the art exists for an optical system, such as system 45, that exhibits maintained etendue.